Known umbrellas have a canopy that can act as a shield against the sun, rain or wind. The canopy is usually roughly dome or cone shaped when in use and is made of flexible material. A frame keeps the canopy in shape and comprises a shaft with pivotally connected ribs radiating out at one end of the shaft and spreaders attached between the shaft and each rib to support the ribs and push them away from the shaft. The ribs are angled or bent towards the shaft to form the shape of the canopy. Many umbrellas are stowable by sliding the spreaders down the shaft and allowing the ribs to move to a position parallel to the shaft so that the canopy collapses and the umbrella is easier to transport or store. Folding umbrellas take this a stage further by also having one or more hinges in each of the ribs so that each rib can fold back on itself when the umbrella is stowed to make the stowed umbrella shorter. In these versions the shaft may also fold or be telescopic to reduce its folded length. Umbrellas are often made from light weight materials so that they are small and light to carry. Lightweight umbrellas are often made from relatively cheap materials and are inexpensive items.
A problem with many types of umbrellas, in particular lightweight, portable folding umbrellas, is that the umbrella can invert when a gust of wind hits the concave underside of the canopy. This pushes the ends of the ribs that hold the canopy in shape away from the shaft, if the end of one or more of the ribs straightens out or bends away from the shaft the canopy can easily invert. Inversion causes the umbrella to be less effective in windy conditions and can lead to damage to the umbrella, for example, the frame can break or bend or the canopy can tear.
We seek to provide an umbrella which is less prone to inversion in high wind conditions.